Mechanism for operating venetian blinds.



F. G. THOMPSON. MECHANISM FOR OPERATING VENETIAN BLINDS.

APPLICATION FILED APR. 20, 1909.

Patented July 6, 1909.

witnesses fwenior W Fr Jar/ck 5.7 urn 0.9071.

Mai 4 WW? flame the dra-wn-up condition, the woodwork being i cud elevation.

upper side f will wind upon-v the "pulleys.

FREDERICK CHARLES THOMPSON, OI" CHRISTCHURCH, NEW ZEALAND.

MECHANISM FOR OPERATING VENETIAN BLINDS.

Specification of Letters Patent.

Patented July 6, 1909.

Application filed April 20, 1908. Serial No. 428,089

To all whom it may concern:

Be it known that I, FREDERICK (TIIARLES TnoMPsoN, a British subject, residing in (.hristchurch, in the Dominion of New Zealand, have invented certain new and useful Improvements in Mechanism for Operating Venetian Blinds, of which the i'ollowingis a specification.

My invention relates to a aratus for raising and lowering Venetian blinds, and seeks to render these operations-more convenient by the use of mechanical means whereby the blind is raised by the action of a spring and retained in the desired position by a check device, the operation being similar to that einployedin raisin and lowering the ordinary spring roller b ind.

With thisnobject in view, the invention consists of th e novel arrangement and comhination-ofjt he various parts which are united to form tlrc'p'resen't device.

Reference-Will now be made to the accompanying drawin s wherein Figurel is rent elevation of a blind in broken away inwarious places in order to show the attached mechanism. Fig. 2 is an Fig. 3 is a plan of the same, the upper part f the, casing-being removed. parts bear the same letter throughoutrr r a is the "blind-:suspended from the headboard b ansof the fiexirbleconnections a in the i1 manner, and c is a horizontal shaft revolubl "mounted in-bearings formed in the brack' v d-which are secured'to the the'headboard b. Upon the shaft 0, beiii'gd'igidly secured thereto, are the pulleys e, tog-the peripheries of which the ends of the lifting-cords f are attached, so that, when the shaftfic issrevolved, the lifting cords The lifting cords f are made flat as shown to allow of winding u on the ulleys. Secured rigidly to the en of the s aft c is the fusee g. To

the largest diameterof the fusee g is attached one end of the cord h, the other end of which i passes downward through a slot provided in the headboard b, is then reeved through the pulle vblock j, and is then carried upward and secured to the headboard or some other convenient point above. To the pulleyblock 3' is attached one end of the helical spring k, the other end of which is secured by I a screw or other convenient means to a fixed i point on the window-frame below. The i helical spring It will therefore assume a vertical or nearly vertical position.

The check device is slmllar to that eniployed in the ordinary spring roller, consisting of a pawl 7., having formed on its lower end a tooth. The pawl l is pivoted to the bracket (1 which forms one bearing for the shaft 0. One end of the shaft 0 is formed with longitudinal recesses m at intervals around its periphery, into which'the tooth of the pawl comes when the raising or lowering operation of the blind. is checked.

' The mechanism is here shown concealed latter will also revolve, thereby causin the fusee g to revolve likewise. By s0 revo vin the fusee y will wind the attached cord 1 upon the periphery of the fusee g, in a direc t1on opposite to that in which the liftingcords were wound uipon the pulleys. The winding of the cord upon the fusee y will, by raising the pulley-block j, elongate, andso draw into greater tension the helical spring 7c. The'energy stored up in the sprin k by virtue of this increased tension wil normally tend, by acting on the cord 71-,to rotate in the opposite direction the fusee g, and with it the shaft 0, and thus cause the lifting cords to wind-upon the pulleysandso raise the blind a am.

When the blind has been brought tmrest in the desired position, the tooth of the pawl I will engage .111 one of the recesses m, and so prevent the shaft from revolving.

In order to raise the blind again, it is drawn down slightly and released. In this way the tooth of the pawl will be disengaged and will continuevto jump the recesses while the shaft is revolving, in exactlythe same manner as the ordinary spring roller blind.

' The operation of the mechanism during the process of raising the'blind is simply a reversal of the lowering rocess, that is, the spring causing the cord 2- on the fusee to unwind, revolves the shaft, thereby winding the lifting cords upon the pulleys.

i The cord hbeing wound upon afusee will allow for the varying weight to be overcome by the spring as the blind is raised.

I claim 1 l. A mechanism for operating Venetian blinds comprising the combination of a revoluble shaft mounted longitudinally in bearings above the head-board of the blind, one end of the shaft being formed with longitudi nal recesses at intervals around its periphery; a pawl having a tooth adapted to engage in such recesses pivoted upon one of the shaft bearings; lifting cords for the blinds pulleys upon the shaft, upon which the lifting cords of the blind are wound; a fusee upon the other end of the shaft, a head board having a slot therein a cord having one end secured to and wound upon such fusee in a direction opposite to that in which the lifting cords are wound, while its other end passes downward through the slot in the head-board and is made fast at a fixed point; a vertically arranged helical spring made fast at its lower end to a fixed point; and a pulley block secured to the upper end of the spring through which the cord wound upon the fusee is passed before being made fast at a fixed point above it, substantiallyas and for the purpose set forth.

1 2. In a mechanism for operating Venetian blinds the actuating device comprising the through the slot in the head-board and is.

made fast at a fixed point;v a vertically arend at a fixed point, and a pulley-block secured to the upper end of the spring through which the cord wound upon the fusee is |passed before being made fast at a fixed i point above it, substantially as and for the I purpose set forth. I

In witness whereof I have hereunto set my hand in the presence of two witnesses.

FREDERICK CHARLES THOMPSON.

Witnesses JOHN HAZLITT UPHAM, OYRIL CARLYON COATES.

ranged helical spring made fast at its lower 

